In Charles Dickens' "A Christmas Carol," what do the ghosts of Christmases present and future represent?

In Charles Dickens' "A Christmas Carol," the ghost of Christmas present represents the lives that Ebeneezer Scrooge touches on a day-to-day basis, yet whom he holds in condenscending scorn. By making Scrooge tour the village in which he lives, and observe the holiday celebrations of those to whom he is related and whom he employs at a miserly wage, the ghost impresses upon Scrooge the joys he misses because of his attitude and the consequences for the Cratchit family of his miserliness. While Bob Cratchit has been a loyal and hardworking employee, Scrooge has yet to acknowledge, let alone display empathy toward, Cratchit and his family, especially the sickly Tiny Tim. By letting Scrooge observe the Cratchits, and gaze upon Tiny Tim's crutch, the ghost of Christmas present is presenting Scrooge with the responsibilities a man in his position has towards his fellow man. When Scrooge inquires of the apparition about Tim's prognosis, the ghost replies, "if these shadows remain unaltered by the future (i.e., if Scrooge does not change his ways), the child will die." When Scrooge is forced to reflect upon his attitude to the Cratchit family, and to people in general, he begins to see the error of his ways.

The ghost of Christmas present repeatedly uses Scrooge's own words to force the miserly old man to repent. When they are observing the less fortunate, the ghost quotes Scrooge's earlier rhetorical question, "are there no prisons, no workhouses?" Hearing his own words come out of the ghost's mouth fundamentally changes Scrooge. By representing Scrooge, the ghost enlightens him about his proper role in society.

The ghost of Christmas Yet to Come (or Future) represents, as the moniker suggests, a vision of what the future holds in store for Scrooge should he fail to repent. A truly frightening apparition, the ghost of Christmas Yet to Come represents Death -- and not just Death, but the lonely, isolated existence of a man who kept the world away through displays of contempt and would die alone, his remains buried in a grave unvisited by any friend or family. Before being shown his grave, Scrooge is able to overhear the townspeople he scorned for so long remark upon his passing in a way that further cements his image as a hated man.

The gift of the ghost of Christmas Yet to Come is the epitaph to which Scrooge is lead to exclaim: "Men's courses will foreshadow certain ends, to which, if perservered in, they must lead. But if the courses be departed from, the ends will change."